1. Field of the Invention
The present invention relates to a method for dyeing keratin-containing fibers, in particular, human hair, in which, after a dyeing step, some of the previously dyed fibers are selectively subjected to incomplete, oxidative color removal for the nuancing. In addition, the invention provides a kit-of-parts comprising a dyeing composition and a color removal agent, and application aids, and the use of this kit in the dyeing method according to the invention.
Human hair is nowadays treated in diverse ways with hair cosmetic preparations. These include, for example, the cleansing of the hair with shampoos, the care and regeneration with rinses and treatments, and the bleaching, dyeing and shaping of the hair with dyeing compositions, tinting compositions, waving compositions and styling preparations. In this respect, compositions for changing or nuancing the color of head hair play a prominent role. Disregarding the bleaching compositions which bring about an oxidative lightening of the hair by breaking down the natural hair dyes, then in the field of hair dyeing essentially four types of hair dyeing compositions are of importance.
For permanent, intense colorations with corresponding fastness properties, so-called oxidation dyeing compositions are used. Such dyeing compositions usually comprise oxidation dye precursors, so-called developer components and coupler components. The developer components form the actual dyes under the influence of oxidizing agents or of atmospheric oxygen with one another or with coupling with one or more coupler components. The oxidation dyeing compositions are indeed notable for excellent, long-lasting coloring results. However, for colorations which appear natural, it is usually necessary to use a mixture of a relatively large number of oxidation dye precursors; in many cases, in addition, direct dyes are used for the nuancing.
The developer components used are usually primary aromatic amines with a further free or substituted hydroxy or amino group located in the para or ortho position, diaminopyridine derivatives, heterocyclic hydrazones, 4-aminopyrazolone derivatives and 2,4,5,6-tetraminopyrimidine and derivatives thereof.
Specific representatives are, for example, p-phenylenediamine, p-tolylenediamine, 2,4,5,6-tetraminopyrimidine, p-aminophenol, N,N-bis(2-hydroxyethyl)-p-phenylenediamine, 2-(2,5-diaminophenyl)ethanol, 2-(2,5-diaminophenoxy)ethanol, 1-phenyl-3-carboxyamido-4-aminopyrazolone-5,4-amino-3-methylphenol, 2-aminomethyl-4-aminophenol, 2-hydroxy-4,5,6-triaminopyrimidine, 2,4-dihydroxy-5,6-diaminopyrimidine, 2,5,6-triamino-4-hydroxypyrimidine and 1,3-N,N′-bis(2-hydroxyethyl)-N,N′-bis(4-aminophenyl)diaminopropan-2-ol.
The coupler components used are generally m-phenylenediamine derivatives, naphthols, resorcinol and resorcinol derivatives, pyrazolones and m-aminophenols. Suitable coupler substances are, in particular, 1-naphthol, 1,5-dihydroxynaphthalene, 2,7-dihydroxynaphthalene and 1,7-dihydroxynaphthalene, 5-amino-2-methylphenol, m-aminophenol, resorcinol, resorcinol monomethyl ether, m-phenylenediamine, 1-phenyl-3-methylpyrazolone-5, 2,4-dichloro-3-aminophenol, 1,3-bis(2,4-diaminophenoxy)propane, 2-chlororesorcinol, 4-chlororesorcinol, 2-chloro-6-methyl-3-aminophenol, 2-methylresorcinol, 5-methylresorcinol and 2-methyl-4-chloro-5-aminophenol.
For temporary colorations, use is usually made of dyeing or tinting compositions which comprise so-called direct dyes as coloring component. These are dye molecules which attach directly to the hair and require no oxidative process for color formation. These dyes include, for example, henna, which is known for coloring bodies and hair since antiquity. These colorations are generally considerably more sensitive to shampooing than the oxidative colorations, meaning that an often undesired nuance shift or even a visible “decoloring” takes place very much more quickly.
(2) Description of Related Art, Including Information Disclosed Under 37 C.F.R. §§ 1.97 and 1.98
Finally, a further dyeing method has received great attention. In this method, precursors of the natural hair dye melanine are applied to the hair; in the course of oxidative processes within the hair, these then form nature-analogous dyes. Such a method using 5,6-dihydroxyindoline as dye precursor has been described in EP-B1-530 229. Upon, in particular, repeated, application of compositions comprising 5,6-dihydroxyindoline it is possible to give back the natural hair color to people with gray hair. The color formation here can take place with atmospheric oxygen as the sole oxidizing agent, meaning that it is not necessary to have recourse to any further oxidizing agents. For people with originally mid-blonde to brown hair, the indoline can be used as the sole dye precursor. For application on people with originally red and, in particular, dark to black hair color, by contrast, satisfactory results can often only be achieved through the co-use of further dye components, in particular, specific oxidation dye precursors.
Another way of dyeing keratin-containing fibers is to use dyeing compositions which comprise a combination of component                A compounds which comprise a reactive carbonyl group with component        B compounds chosen from (a) CH-acidic compounds, (b) compounds with primary or secondary amino group or hydroxy group chosen from primary or secondary aromatic amines, nitrogen-containing heterocyclic compounds and aromatic hydroxy compounds, (c) amino acids, (d) oligopeptides constructed from 2 to 9 amino acids.        
The corresponding dyeing method (called oxo dyeing below) is described, for example, in the publications WO-A1-99/18916, WO-A1-00/38638, WO-A1-01/34106 and WO-A1-01/47483. Some of the resulting colorations have color fastnesses on the keratin-containing fibers which are comparable to those of oxidation dyeing. The nuance spectrum which can be achieved with the gentle oxo dyeing is very broad and the coloration obtained often has an acceptable brilliance and depth of color. The above-mentioned components A and B, referred to below as oxo dye precursors, are generally themselves not dyes, and therefore when taken by themselves are not suitable for dyeing keratin-containing fibers. In combination, they form dyes in a nonoxidative process. Among compounds of component B, however, corresponding oxidation dye precursors of the developer and/or coupler type can also be used with or without the use of an oxidizing agent. Thus, the method of oxo dyeing can be readily combined with the oxidative dyeing system.
Methods are known to the person skilled in the art in which the hair is lightened or bleached on selective areas through the application of so-called bleaching agents. The result of these methods, e.g., on undyed hair which has been left natural are, for example, blonde strands or lightened hair ends.
The oxidizing agents present in the bleaching compositions have an oxidizing effect on the natural hair dye melanin and optionally on synthetic dyes located in the fiber and thereby cause a color change and optimally lightening of the hair color. The principles of bleaching processes and oxidative dyeing processes are known to the person skilled in the art and are summarized in relevant monographs, e.g., by K. Schrader, Grundlagen und Rezepturen der Kosmetika [Principles and formulations of cosmetics], 2nd edition, 1989, Dr. Alfred Hüthig Verlag, Heidelberg, or W. Umbach (ed.), Kosmetik (cosmetics), 2nd edition, 1995, Georg Thieme Verlag, Stuttgart, N.Y.
For the lightening or ultrableaching of human hair—particularly for strand application—solid or paste-like preparations comprising solid oxidizing agents are usually mixed directly prior to application with a dilute hydrogen peroxide solution. This application mixture is then applied to the hair and rinsed out again after a certain contact time. Besides hydrogen peroxide, the conventional ready-to-use bleaching compositions for keratin-containing fibers in most cases comprise peroxydisulfate compounds for increasing the lightening capacity and, upon application to the fibers, have a pH greater than pH 9. However, the result of a lightening operation should be differentiated from the result of the ultrableaching. Whereas during the ultrableaching operation as far as possible all of the color pigments are oxidatively influenced with retention of a virtually white-colored hair fiber, in the case of oxidative lightening, the existing coloration should be nuanced (i.e., lightened) in such a way that the starting color is still recognizable, but appears lighter in color to the observer.
However, the desired oxidative lightening of keratin-containing fibers treated with dyeing compositions cannot be effected directly. Often, the oxidative lightening of such color-changed fibers results in undesired color shifts to, e.g., orange or green tones, which unquestionably have to be avoided. In the course of lightening, the only color effects which are desirable are those which signify a lightening of the starting shade. In addition, it is desirable to uniformly nuance a well-defined part of the head hair, such as, for example, strands and to distribute these well-defined parts again as uniformly as possible over the entire head hair area. For strand nuancing, this means that a hair fiber has to be nuanced uniformly from the roots of the hair to the ends and these strands should settle as evenly distributed as possible both in the covering hair and also in the areas of hair which are underneath. In this way, uniform and natural-looking, lightened color reflections are obtained.